Presently, endoscopic vessel harvesting is conducted in multiple steps. In one procedure, a surgeon inserts a cannula having a lumen housing an endoscope and a transparent tapered tip encasing the distal end of the cannula into an incision. The surgeon advances the cannula under endoscopic visualization through the transparent tip along the sides of a vessel to be harvested to dissect the vessel away from surrounding connective tissue. Then, in order to perform any other surgical procedure, the cannula must be withdrawn from the incision to detach the transparent tapered tip from the cannula to provide an open distal end. The open distal end permits endoscopic shears or other surgical tool to be extended out of the cannula and into the surgical site to perform a surgical procedure, such as cauterization and transection of vessel side branches in a saphenous vein harvesting procedure. As the transection is performed under endoscopic visualization, the cannula must be sufficiently large to accommodate both the endoscope and endoscopic shears. Thus, a cannula having a lumen that can accommodate an endoscope (typically 5 mm) and having at least one other lumen of sufficient diameter to accommodate a surgical tool such as endoscopic shears (typically 5 mm) must have a shaft that is typically 12 mm in diameter. Accordingly, a vessel harvesting cannula with a smaller distal profile is desired to improve maneuverability and to decrease dissection force required to advance the cannula through connective tissues.